Plate burner for photoengraving



Feb '1, 1950 Pow s v 2,496,814

PLATE BURNER FOR PHOTOENGRAVING Filed Sept. 50, 1947 2 Sheets-Sheet 1 v INVENTOR FRANK T OWERS BY v MAM, W m-rTQRNEYs Feb. 7, 1950 F. T. POWERS 2,496,814

PLATE BURNER FOR PHOTOENGRAVING Filed Sept. 30, 1947 v 2 Sheets-Sheet 2 70 0 r Y 72 94 24 24 Z 22 3 m INVENTOR NEYJ Patented Feb. 7, 1950 UNITED STATES PATENT OF'F ICIE PLATE BURNER FOR PHOTOENGRAVING Frank Powers, Glen Cove, N. Y.; Frank '1. Powers, Jr., and John M. Power's, executors of said Frank T. Powers, deceased, assign'ors to Powers Photo Engraving Company, a corporation' of New York 3 Claims.

The present invention relates to a novel and improved plate burner or burning-in stove for use in photoengraving.

Objects and advantages of the invention will be set forth in part hereinafter and in part will be obvious herefroin, or may be learned by practice with the invention, the same being realized and attained by means of the instrumental'ities and combinations pointed out in the appended claims.

The invention consists in the novel parts, constructions, arrangements, combinations and improvements herein shown and described.

The accompanying drawings, referred to herein and constituting a part hereof, illustrate one embodiment of the invention, and together with the description, serve to explain the principles of the invention.

Of the drawings:

Figure 1 is a side elevation, with parts broken away, of the present preferred and illustrative embodiment of the invention;

Figure 2 is a sectional view taken on the line 2-2 of Figure 1;

Figure "3 is a fragmentary detailed section taken on the line 33 of Figure 1; and

Figure 4 is a circuit diagram showing the electrical connections as used in the illustrative embodiment.

The present invention has for its object the provision of a novel and improved burning-in stove for photoengraving use which gives greater uniformity of heating of the plate than has heretofore been possible. A further object of the invention is the provision of a stove for photoengraving use which provides for different rates of heating of the plate, and in which the plate need not be manipulated during the time of heating. Still another object of the invention is the provision of an automatic plate burner in which the plate is constantly moved with respect to the source of heat during the heating operation so that the plate is uniformly heated notwithstanding the fact that the source of heat may not distribute the'heat uniformly.

In accordance with the present invention, there is provided a plate carrier adapted to receive a photoengraving plate such as a halftone or line engraving, which carrier is movable into and out of a casing, and while within the casing, the plate is subjected to relatively intense heat so as to burn-in the exposed and developed photosensitive resist, usually bichromated gelatin, or to melt the etching powder which has been applied to the partially etched plate, this etching powder vent I.

2 usually being dragons blood or some equivalent resin. Various sources of heat may be used but I prefer to use two series of gas burners, inasmuch as gas is usually more economical than infra-red lamps or other sources of heat which can be used for this purpose.

Means are provided for automatically turning on the gas as soon as the plate carrier has been moved into the casing and into heating position, and other means are provided for constantly reciprocating the plate carrier while it is within the seems and in heating position so that the heat is uniformly distributed over the plate, and no excessive heating of the metal "takes place. These reciprocating means are optionally operated so that the plate carrier may be reciprocated or not during the heating operation, and the heating means preferably include selectively operable means so that a portion of the heat-- ing means are in operation when the plate reciprocating means are operated, and additional heating means may be optionally brought into operation when the reciprocating means are not used. Means are also provided 'for engaging and disengaging the reciprocating means with respect to the plate carrier so as to permit the operator to withdraw the plate carrier and the plate carried by it from the casing when the heating operation has been completed.

Referring now in detail to the accompanying drawings, which illustrate a typ'ical'and preferred embodiment of the present invention, there is provided a 'casing l0 connected to an exhaust Within the casing and at a convenient horizontal level are twoseries of gas burners l2 and I3 of the type ordinarily used in burning-in stoves, these burners being distributed over the horizontal area of the casing so that the flames of each set are substantially uniformly spaced. The burners l2 and 13 are fed with gas from the supply line 14 through electromagnetic valves [5 v and "5, these valves serving to open the line to full intensity while they are energized, and to close the line when deenerg-ized so to reduce the flame until it is just sufficiently large to keep the burners lit, the gas then being supplied through the by-passes I5 and It. The series of burners l2 and I3 are preferably arranged parallel to each other and across the path of movement of the plate as it is moved into '01 out of the casing. The burners 12 and [3 are supported on rails 1-6 extending from "one side wall l8 to another of the easing, and in the case of gas burners the source of heat is prefer- 3 ably positioned below the plate and its path of movement.

The plate carrier comprises a pair of side rails 20 which are connected at their ends by rods 22 and 23, as well as by intermediate rods 24, the intermediate rods serving to support a series of thin parallel metal straps 25 which are mounted edgewise and whose upper surfaces form a support for the plate to be heated or burned-in. At its forward end the plate carrier is provided with rollers 21 which are rotatably mounted on the ends of rod 23 and run in channels 29 which are horizontal, parallel to each other and supported at their ends by the vertical angle members 3| at the corners of the casing. Means are provided for supporting the outer or rearward end of the plate carriers, and comprise the links 32 which are pivotally mounted on the ends of rod 22, the lower ends of the links being connected by a rod 34 at the ends of which are rollers 36 which slide in the vertically disposed channels 38.

Links 32 are pivotally connected to links 46 which are mounted on brackets 48 secured to the wall I8, and are pivotally connected to the links 32 by pivot 50.

Means are also provided for preventing the carriage from moving in too rapidly into the heating chamber, and for this purpose the lower cross rod 34 is engageable with the outer ends of pivotally mounted levers 39, the inner ends of which are pivoted at 40 on brackets 4|. Intermediate their ends levers 39 are connected to tension springs 43 the upper ends of which are secured to eyes 44 mounted in the casing wall I8. As the carrier approaches its forwardmost position, its speed is checked by the tensioning of spring 43.

The plate carrier thus constructed may be easily moved into and out of the stove casing so as to bring a plate supported by the strips 25 directly above the heating means I2 and I3, while link 46 serves to support the outer end of the casing and lever 39 serves to prevent a too rapid movement of the plate carrier into the casing, the action of spring 43 being such as to slow the plate carrier as it moves into the casing.

Means are provided for continually reciprocating the plate carrier while it is in burning-in position, and these means preferably comprise an electric motor 60 driving crank 6I' through speed reduction gearings 52. an axis transverse to the movement of the plate carrier, and is a variable throw crank of conventional form connected to adjustable link 64. The other end of link 63 is pivotally connected to an adjustable bracket 66 which can be moved to different positions along the vertical rod 61 and secured in the desired position by tightening set screw 68. The upper end of the rod 61 is connected to the inner end of link which extends far enough so that the slot II at its outer end may engage with rod I2 which extends between and is connected to links 32. Link 19 is supported and guided by means of antifriction roller I4 which is rotatably mounted on bracket which in turn is carried by the support 16 fastened to the side walls of the casing. Resilient means such as spring I8 connecting link 10 with an eye I9 are provided for holding the link It! down and in en gagement with rod 12.

As motor 60 operates, the crank 6| slowly rotates causing a corresponding reciprocation of the link 10 which is imparted to the plate carrier so as to move the plate carried thereby back and forth over the banks of gas flames heating the plate.

Crank 6| is arranged on Means are provided for manually controlling the supply of power to the motor 60 and the supply of gas through valve I5 to the bank I2 of burners and also for simultaneously engaging link Ill with the plate carriage so that the motor 69 is energized, gas burners brought to full intensity, and the link connection for driving the plate carriage are all simultaneously effected by operation of a single manual control. As embodied there is provided an eccentric secured to shaft 8|, journalled in the opposite side walls 82 of the casing I0, the eccentric serving in one position to lift the link I0 sufficiently so that its slotted end II is raised out of the path of rod I2, or alternatively to lower the link I0 so as to establish the driving connection between crank GI and the plate carriage. At one outer end of shaft 8| is provided another eccentric 83 so related to eccentric 80 that motor switch 85 is closed as the link I0 is lowered into driving position, while the other end of shaft BI is provided with a hand lever 89 by which the shaft 8| and its eccentrics 80 and 83 may be conveniently moved from one position to the other.

Means are also provided for optionally energizing the electromagnetic valves I5 and I6 so that the burners I2 and I3 are brought to full intensity when it is desired to exercise manual control over the burning-in process. For this purpose, a switch 88 is provided on the rear wall I8 of the casing, and is engaged by bar 23 when the plate carrier is moved completely into the casing. Movement of the plate carrier to this position closes switch 88 so as to open valves I5 and I6 completely and thereby supply a full flow of gas to the burners I2 and I3.

Figure 4 of the drawings illustrates diagrammatically the electrical connections of the various electrical parts used in the preferred embodiment. As illustrated, power is derived from a suitable source 99 and is supplied through the main switch 9| to conductors 92 and 93. For convenience in observing the interior of the machine and the extent of melting or burning-in of the resist on the plate, a lamp 94 is provided within the casing and is supplied with power through switch 95 from the conductors 92 and 93. When the manual lever 86 has been swung to close switch 85, current is supplied to motor 60 through switch 85 from the conductors 92 and 93, and simultaneously the coil 96 of relay 9'! is energized so as to connect contacts 98 and 99 by bridge I 00 thereby supplying current to the coil IOI of the electromagnetic valve I5, thereby increasing the flow of gas to the burners I 2 so that these burners deliver their full heat while the motor 60 is driving the plate carrier.

When the plate carrier is moved fully into the casing, switch 88 is closed and thereby current is supplied through it from conductors 92 and 93 through the winding I02 of electromagnetic valve I6, and valve I5 is opened by current supplied to coil IOI through bridge I00 which is then in contact with contacts I 93 and I04, inasmuch as coil 96 of relay 91 is not energized. With both valves I5 and I6 fully opened, burners I2 and I3 are thus automatically brought to full heat whenever the carriage is manually moved to its innermost position.

The plate burner of the present invention thus provides a single burning-in stove by which a photoengraved plate, such as a line engraving which has been partially etched and powdered, can be intensely heated under manual control, the burners being automatically brought to full heating position manually by moving the carriage into heating position, and also provides a stove which is adapted for the slower and more uniform degree of heating required for the burning-in of the developed bichromated resist, such as is used in the halftone engraving process.

The invention in its broader aspects is not limited to the specific mechanisms shown and described but departures may be made therefrom within the scope of the accompanying claims without departing from the principles of the invention and without sacrificing its chief advantages.

What is claimed is:

1. A photoengraving stove including in combination a source of heat, a support to position a plate to be heated by said source, means for moving said support and plate back and forth relative to said source while the plate is being heated so as to distribute the heat on said plate, a motor, a crank and link interconnecting the motor and support the link being detachably engageable with the support, a manually actuated eccentric controlling the engagement and disengagement of the link with the support, and means controlling said source of heat and actuated in common with the eccentric so that the link is positioned for engagement with the support as the heat is turned on.

2. A photoengraving stove including in combination a source of heat, a support to position a plate to be heated by said source, means for moving said support and plate back and forth relative to said source while the plate is being heated so as to distribute the heat on said plate, a motor, a crank and link interconnecting the motor and support the link being detachably engageable with the support, a control means for the source of heat, and a handle for moving said control means and simultaneously positioning the link for driving engagement with the plate support.

3. A photoengraving stove including a plurality of sources of heat, a support to position a plate to be heated by one or more of said sources mounted for horizontal movement relative to said sources, a motor, means interconnecting said motor and support for reciprocating the latter while the plate is heated said means including a crank connected to said motor and a link connected to said crank and detachably engageable with said support, control means actuated by movement of the support to a particular position for energizing all of said sources, and additional manual means for alternatively energizing a portion of said sources while the support is horizontally moved, said manual means comprising common means for energizing the motor, engaging said link with said support, and energizing a portion of the sources of heat, said common means including an eccentric positioning the link for engagement with the support.

FRANK Tv POWERS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 633,819 Dobson Sept. 26, 1899 1,744,409 Morrisson -1 Jan. 21, 1930 1,888,596 Hopkins Nov. 22, 1932 2,158,158 Shea May 16, 1939 2,273,126 McGillin Feb. 17, 1942 FOREIGN PATENTS Number Country Date 296,127 Germany Jan. 13, 1917 

